Some conventional wireless networks adopt a central authority to manage communications between the nodes of the network and allocate rates for the communications. For example, in a conventional state of the art cellular network, the nodes of the network may include cellular telephones, and other mobile devices configured for enhanced multimedia applications. The communications between such nodes may include both voice and non-voice data traffic, with requirements or preferences for a variety of data rates based on the application.
FIG. 1 depicts an exemplary conventional cellular network 100. A central authority 110, such as a base station is commonly employed to manage the traffic and allocate data rates in cellular network 100. The devices at any two nodes of the cellular network 100, such as 104 and 106 may communicate with each other by routing all communications via the central authority 110. The communication link between a node and central authority 110 is commonly referred to as a “single hop.” Links 120, 130, 140 and 150 represent single hops between nodes 102, 104, 106 and 108 respectively and central authority 110.
Some current technology is limited to single hops. Consequently, in some instances, this current technology does not permit efficient communication between the two nodes 104 and 106 without the involvement of central authority 110. The involvement of the central authority 110 leads to well known problems, such as, for example in cellular phone networks: dropped calls, low reception, increased drain on battery life, etc., because the devices at individual nodes may not always be located at sufficient proximity to the base station, or the base station may be limited in the amount of traffic it can handle.
Accordingly, multi-nodal network implementations that do not always depend on a central authority for certain functions have been explored. Such implementations are commonly known as “distributed” or “ad-hoc” networks, wherein each node is configured to manage its own data transmission without always requiring relatively heavy involvement of a central authority. A common problem encountered in distributed network implementations is that of interference among several communicating nodes located in close proximity to one another. Another problem is the issue of efficient resource allocation of the wireless medium. Data intensive applications are commonly supported by mobile devices, and without a central authority to handle resource allocation, some nodes may consume the available communication channel while starving other nodes.
Therefore, certain existing implementations of distributed networks have been limited by requiring knowledge at each node of other nodes in the system in order to allocate system resources among the nodes. However, over a large number of nodes, and with high data traffic, some implementations known in prior art are often rendered very inefficient, leading to high overheads and low throughputs. Accordingly, there is a need in the art for distributed rate allocation among the several nodes in a throughput-optimal or throughput-cognizant manner, wherein interference is minimized or reduced and knowledge at each node of every other node is not required.
Further, certain wireless networks, including single hop and multi-hop, centralized and decentralized wireless networks, do not adequately select the rate at which constituent wireless devices, or nodes, attempt to transmit data. Selecting an appropriate rate may be particularly challenging when wireless devices use shared resources of a wireless medium, e.g., shared frequencies, shared times, shared codes, and in systems with beam forming, shared directions, or other orthogonalizations, and combinations thereof; for example. For instance, in some wireless networks, wireless devices attempt to maximize the rate of transmission of that wireless device without adequately accounting for the effect of that transmission on the ability of other wireless devices to share the same shared resources of the wireless medium, potentially resulting in a lower collective date rate for the network as a whole. Additionally, in some wireless networks, wireless devices do not share the same resources of the wireless medium, in part, because it is difficult to determine whether the transmissions of one wireless device are colliding with the transmissions of another wireless device and preventing resolution of signals from the other wireless device.